Effect of Al on the Microstructure and Mechanical Properties of Mg–Sn–Ca–Mn Wrought Alloy

Yun Feng,Yuanyuan Yang,Zongqi Xiao,Xianglong Meng,Guorong Zhou,Jinfeng Leng,Xinying Teng 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

Mg–Sn–Ca–Mn–xAl (x = 0,1.5 wt%) alloys with ultra-fine recrystallized grains were prepared by conventional extrusion(400 °C, 0.5 mm/s). Effects of aluminum (Al) on mechanical properties and microstructure of the Mg–1Sn–1Ca–0.5Mn(wt%) alloy were systematically investigated. By the addition of 1.5 wt% Al, the yield strength of the as-extruded alloysignificantly increased from 183 to 237 MPa. The as-cast alloys show a dendritic structure consists of α-Mg, (Mg, Al)2Ca,and CaMgSn phases. The as-extruded Mg–1Sn–1Ca–0.5Mn–1.5Al alloys exhibit a bimodal grain structure composed ofdynamic recrystallized (DRXed) fine grains and coarse unDRXed grains. Compared with Al free alloy, a lot of nano-scaleplanar Al2Caand rectangle shape Al8Mn5precipitated in the as-extruded alloy with 1.5 wt% Al. Meanwhile, the addition ofAl significantly strengthened alloys’ fiber texture with < 10–10 >//ED.

Explored a Cryptic Plasmid pSXM33 from Shewanella xiamenensis BC01 and Construction as the Shuttle Vector

Yunli Zhou,I-Son Ng 한국생물공학회 2016 Biotechnology and Bioprocess Engineering Vol.21 No.1

Plasmids are essential tools for gene transfer and manipulation in many kinds of microorganisms, but they remain mysterious in the Shewanella species. Herein, a novel cryptic plasmid pSXM33 was isolated from marine bacterium Shewanella xiamenensis BC01 (SXM) and followed by sequencing and characterization through bioinformatics approaches. At first, the plasmid DNA was digested to relatively short fragments, sub-cloned into vector pMD19T-Simple and pBluescript SK(II), then transformed into Escherichia coli (E. coli) DH5α for sequencing. A full-length pSXM33 nucleotide sequence revealed 8,068 bp with GC content of 44%, containing 12 putative open reading frames (ORFs) and several unique restriction sites. Based on the annotation of sequences, ORF1 and ORF4 showed the highest similarity to the integrase, while ORF3, ORF7 and ORF8 encoded the replication protein RepB, plasmid stabilization protein and CopG family transcriptional regulator, respectively. The promoter prediction and tandem repeats analyses suggested 15 promoters and multiple tandem repeats. Moreover, pETSXM1 and pETSXM2 were successfully constructed as shuttle vectors for E. coli and Shewanella species, based on the repB from pSXM33 and a kanamycin resistance gene from vector pET28a(+) as a selective marker. These results provide a useful genetic tool for new insight into molecular level study of the Shewanella species.

Association Between Single Nucleotide Polymorphisms in the XRCC1 Gene and Susceptibility to Prostate Cancer in Chinese Men

Zhou, Yun-Feng,Zhang, Guang-Bo,Qu, Ping,Zhou, Jian,Pan, Hui-Xin,Hou, Jian-Quan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.10

Background: Prostate cancer (Pca) is one of the most common complex and polygenic diseases in men. The X-ray repair complementing group 1 gene (XRCC1) is an important candidate in the pathogenesis of Pca. The purpose of this study was to evaluate the association between single nucleotide polymorphisms in the XRCC1 gene and susceptibility to Pca. Materials and Methods: XRCC1 gene polymorphisms and associations with susceptibility to Pca were investigated in 193 prostate patients and 188 cancer-free Chinese men. Results: The c.910A>G variant in the exon9 of XRCC1 gene could be detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing methods. Significantly increased susceptibility to prostate cancer was noted in the homozygote comparison (GG versus AA: OR=2.95, 95% CI 1.46-5.42, ${\chi}^2$=12.36, P=0.001), heterozygote comparison (AG versus AA: OR=1.76, 95% CI 1.12-2.51, ${\chi}^2$=4.04, P=0.045), dominant model (GG/AG versus AA: OR=1.93, 95% CI 1.19-2.97, ${\chi}^2$=9.12, P=0.003), recessive model (GG versus AG+AA: OR=2.17, 95% CI 1.33-4.06, ${\chi}^2$=8.86, P=0.003) and with allele contrast (G versus A: OR=1.89, 95% CI 1.56-2.42, ${\chi}^2$=14.67, P<0.000). Conclusions: These findings suggest that the c.910A>G polymorphism of the XRCC1 gene is associated with susceptibility to Pca in Chinese men, the G-allele conferring higher risk.

Effect of fermented blueberry on the oxidative stability and volatile molecule profiles of emulsion-type sausage during refrigerated storage

Zhou, Hengyue,Zhuang, Xinbo,Zhou, Changyu,Ding, Daming,Li, Chunbao,Bai, Yun,Zhou, Guanghong Asian Australasian Association of Animal Productio 2020 Animal Bioscience Vol.33 No.5

Objective: The aim of this work was to assess the effect of fermented blueberry (FB; 2%, 4%, and 6%) on the oxidative stability and volatile molecule profiles of emulsion-type sausage stored at 4℃ for 28 days. Methods: The antioxidant activity of FB was determined through radical-scavenging activity against 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals. Four formulations of sausage treatments with different FB levels (0%, 2%, 4%, 6%) were prepared, then peroxide value (POVs), thiobarbituric acid-reactive substances (TBARS) values, protein carbonyls and thiol groups were measured. The aroma profiles of sausages for each treatment was also determined. Results: The half maximal inhibitory concentration indicated that FB had greater scavenging ability than ascorbic acid against DPPH and hydroxyl radicals. Sausages with FB significantly retarded increases in POVs and TBARS, as well as in the content of protein carbonyls during all storage days (p<0.05). Particularly, 4% and 6% FB-treated sausages had better oxidation inhibition effects. However, FB accelerated the reduction in thiol groups (p<0.05). Additionally, FB inhibits the excessive formation of aldehyde compounds; for example, hexanal, which may cause rancid flavors, decreased from 58.25% to 19.41%. FB also created 6 alcohols (i.e., 2-methyl-1-propanol, 3-methyl-1-butanol, and phenylethyl alcohol), 5 ester compounds (i.e., ethyl acetate, ethyl lactate, and ethyl hexanoate) and 3-hydroxy-2-butanone in the sausages that contribute to sausage flavors. The principal component analysis showed that the aroma profiles of sausages with and without FB are easily identified. Conclusion: The addition of FB could significantly reduce the lipid and protein oxidation and improve oxidative stability for storage. Also, adding FB could inhibit rancid flavors and contribute to sausage flavors.

Multilevel characteristics and memory mechanisms for nonvolatile memory devices based on CuInS₂ quantum dot-polymethylmethacrylate nanocomposites (3 pages)

Zhou, Y.,Yun, D.Y.,Kim, S.W.,Kim, T.W. AMERICAN INSTITUTE OF PHYSICS 2014 APPLIED PHYSICS LETTERS Vol.105 No.23

Optimum study on wind-induced vibration control of high-rise buildings with viscous dampers

Zhou, Yun,Wang, DaYang,Deng, XueSong Techno-Press 2008 Wind and Structures, An International Journal (WAS Vol.11 No.6

In this paper, optimum methods of wind-induced vibration control of high-rise buildings are mainly studied. Two optimum methods, genetic algorithms (GA) method and Rayleigh damping method, are firstly employed and proposed to perform optimum study on wind-induced vibration control, six target functions are presented in GA method based on spectrum analysis. Structural optimum analysis programs are developed based on Matlab software to calculate wind-induced structural responses. A high-rise steel building with 20-storey is adopted and 22 kinds of control plans are employed to perform comparison analysis to validate the feasibility and validity of the optimum methods considered. The results show that the distributions of damping coefficients along structural height for mass proportional damping (MPD) systems and stiffness proportional damping (SPD) systems are entirely opposite. Damping systems of MPD and GAMPD (genetic algorithms and mass proportional damping) have the best performance of reducing structural wind-induced vibration response and are superior to other damping systems. Standard deviations of structural responses are influenced greatly by different target functions and the influence is increasing slightly when higher modes are considered, as shown fully in section 5. Therefore, the influence of higher modes should be considered when strict requirement of wind-induced vibration comfort is needed for some special structures.

Feasibility study of improved particle swarm optimization in kriging metamodel based structural model updating

Yun-Lai Zhou,Shiqiang Qin,Jia Hu,Yazhou Zhang,Juntao Kang 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.70 No.5

This study proposed an improved particle swarm optimization (IPSO) method ensemble with kriging model for model updating. By introducing genetic algorithm (GA) and grouping strategy together with elite selection into standard particle optimization (PSO), the IPSO is obtained. Kriging metamodel serves for predicting the structural responses to avoid complex computation via finite element model. The combination of IPSO and kriging model shall provide more accurate searching results and obtain global optimal solution for model updating compared with the PSO, Simulate Annealing PSO (SimuAPSO), BreedPSO and PSOGA. A plane truss structure and ASCE Benchmark frame structure are adopted to verify the proposed approach. The results indicated that the hybrid of kriging model and IPSO could serve for model updating effectively and efficiently. The updating results further illustrated that IPSO can provide superior convergent solutions compared with PSO, SimuAPSO, BreedPSO and PSOGA.

Preparation and Microwave Absorption Properties of the Fe/TiO2/Al2O3 Composites

Yun Li,Haifeng Cheng,Nannan Wang,Shen Zhou,Dongjin Xie,Tingting Li 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.11

To reduce the imbalance of impedance matching between the magnetic metal nanowires and free space, Fe/TiO2 core/shell nanowire arrays with different diameters were fabricated in the templates of anodic aluminum oxide membranes by electrodeposition. The influences of the microstructure on the microwave absorption properties of the Fe/TiO2/Al2O3 composites were studied by the transmission/reflection waveguide method. It was demonstrated experimentally that both the interfacial polarization and the diameter of the Fe/TiO2 core/shell nanowires have critical effects on the microwave absorption properties. We also investigated the angle dependence of the microwave absorption properties. Due to the interfacial polarization and associated relaxation, the Fe/TiO2/Al2O3 composites exhibited optimal microwave absorption properties when microwave propagation direction was accordant with the axis of the nanowires. Finally, we managed to obtain an optimal reflection loss of below -10 dB (90% absorption) over 10.2–14.8 GHz, with a thickness of 3.0mm and the minimum value of -39.4 dB at 11.7 GHz.

Prefrontal cortex miR-29b-3p plays a key role in the antidepressant-like effect of ketamine in rats

Yun-Qiang Wan,Jian-Guo Feng,Mao Li,Mao-Zhou Wang,Li Liu,Xueru Liu,Xiao-Xia Duan,Chun-Xiang Zhang,Xiao-Bin Wang 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Ketamine has a rapid, obvious, and persistent antidepressant effect, but its underlying molecular mechanisms remain unknown. Recently, microRNAs (miRNAs) have emerged as important modulators of ketamine’s antidepressant effect. We investigated the alteration in miR-29b-3p in the brain of rats subjected to ketamine administration and chronic unpredictable mild stress (CUMS), and a sucrose preference test and forced swimming test were used to evaluate the rats’ depressive-like state. We used recombination adeno-associated virus (rAAV) or lentivirus-expressing miR-29b-3p to observe the change in metabotropic glutamate receptor 4 (GRM4). Cell culture and electrophysiological recordings were used to evaluate the function of miR-29b-3p. Ketamine dramatically increased miR-29b-3p expression in the prefrontal cortex of the normal rats. The dual luciferase reporter test confirmed that GRM4 was the target of miR-29b- 3p. The miR-29b-3p levels were downregulated, while the GRM4 levels were upregulated in the prefrontal cortex of the depressive-like rats. The ketamine treatment increased miR-29b-3p expression and decreased GRM4 expression in the prefrontal cortex of the depressive-like rats and primary neurons. By overexpressing and silencing miR-29b-3p, we further validated that miR-29b-3p could negatively regulate GRM4. The silencing of miR-29b-3p suppressed the Ca2+ influx in the prefrontal cortex neurons. The miR-29b-3p overexpression contributed to cell survival, cytodendrite growth, increases in extracellular glutamate concentration, and cell apoptosis inhibition. The overexpression of miR- 29b-3p by rAAV resulted in a noticeable relief of the depressive behaviors of the CUMS rats and a lower expression of GRM4. The miR-29b-3p/GRM4 pathway acts as a critical mediator of ketamine’s antidepressant effect in depressive-like rats and could be considered a potential therapeutic target for treating major depression disorder.

A Novel Approach to Controlling CaCO₃ Crystalline Assembly by Changing the Concentration of Poly(aspartic acid)

Zhou, Hongjian,Gao, Yanmin,Hwang, Sun-Gu,Lee, Dong-Yun,Park, Jung-Youn,Lee, Jae-Beom Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.11

$CaCO_3$ crystalline structures having novel assemblies were in situ fabricated as analogs of naturally occurring proteins and polysaccharides for biomineralization. The calcite crystal was mineralized in a poly(vinyl alcohol)-$Ca^{2+}$ complex film immersed in a $Na_2CO_3$ solution containing poly(aspartic acid). The morphology and size of the $CaCO_3$ crystals were tuned by varying the concentration of poly(aspartic acid). The mechanisms of their nucleation orientation and formation were investigated experimentally and through molecular dynamics (MD) simulations in order to obtain a better understanding of the interactions between the polymers and the crystal at the molecular level. Both the MD results and experimental results indicate that the interaction between PVA and calcite mainly depends on the concentration of the polymer. The novel approach proposed herein for the fabrication of inorganic crystalline assembly structures can be used to fabricate precise crystalline structures.